The invention relates to a control unit for a motor vehicle, an electronic immobilizer and a method for irreversible deactivation of an electronic interface.
Control units for motor vehicles are usually manufactured by automobile suppliers. Before shipping the control units to the respective vehicle manufacturers, the software program, i.e., the sequence control to be executed by the control unit equipped with a microprocessor after being installed in the vehicle by the manufacturer is entered into the electronic memory of the control unit. The traditional control unit has two interfaces. The first interface of the control unit is used for transmitting the sequence control to the memory of the control unit in an operation performed at the suppliers. The second interface is for the vehicle electronics, i.e., the vehicle electric system, to communicate with the control unit after the control unit has been installed in the vehicle. The first interface is often a so-called debugging interface on the circuit board of the control unit which is contacted by needle adapters or the like.
The first interface is no longer needed after the control unit is shipped. Instead, there is a risk that after the control unit has been installed in the vehicle, the control unit might be reprogrammed, i.e., reflashed, via this first interface for the purpose of manipulation. In the case of a control unit that is part of the electronic immobilizer of the vehicle, the manipulation can consist of canceling, i.e., reprogramming the electronic immobilizer. Another manipulation is so-called chip tuning, i.e., use of a modified engine control for the purpose of increasing power and with the disadvantage of a shortened lifetime. Finally, the manipulation may consist of changing the mileage reading to obtain a higher selling price for the vehicle.
If the vehicle manufacturer has already installed the control unit in the vehicle, said control unit having been equipped by the supplier with a sequence control, the control unit is furnished with manufacturer data using security codes via the plug-in diagnostic connection.
The object of this invention is to prevent manipulations on the data present in a control unit for a vehicle.
This object is achieved by a control unit, an electronic immobilizer and a method for irreversible deactivation of an electronic interface. Advantageous embodiments of the invention are described below.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.